Second Wizarding War

Crabbe was one of the few Death Eaters who returned to Lord Voldemort when he rose to power again in 1995. Voldemort was displeased when he learned that Crabbe didn't attempt to find him, but he forgave him.

Battle of the Department of Mysteries

"We'll split into pairs and search, and don't forget, be gentle with Potter until we've got the prophecy, you can kill the others if necessary..."

During the Second Wizarding War, Crabbe participated in the Battle of the Department of Mysteries in 1996, and was paired with Rabastan Lestrange during the pursuit of the six D.A. members. He went with Rabastan to try and capture Harry, Hermione, and Neville, who were hiding in the Time Chamber. His part in trying to find them ended shortly; he was Stunned by Harry, and Crabbe fell and knocked over a grandfather clock. He was likely imprisoned in Azkaban, but re-escaped in 1997.

Battle of Hogwarts

During the Battle of Hogwarts in 1998, Crabbe's son Vincent (who had also become a Dark Wizard) died by the effects of his own Fiendfyrecurse. Crabbe's reaction over his son's death is unknown. Crabbe fought at the Battle of Hogwarts too.

Post-war

Crabbe was presumably imprisoned in Azkaban after Voldemort's final defeat.

Notes and references

↑See this interview; “Samantha: Was Snape the only Death Eater who could produce a full Patronus?
J.K. Rowling: Yes, because a Patronus is used against things that the Death Eaters generally generate, or fight alongside. They would not need Patronuses.”